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I got my patch cable back from TwiZted Biker today and tried to create a new ignition curve but found out in a phone call to Dynatek that even though the SE module with 4 ignition curves was made by Dynatek back in the day, It is not programable like the 2ki or the 2000p modules..
So I had to go back to curve 2 but advanced the entire curve by 5*.. Didn't really want to do it that way but have no choice right now. I will say by running the motor like this, there is a very noticeable difference in power.. I really like it and so does the motor.. No detonation and the plugs look really good.. Throttle response has also increased.. I wanted a little different curve but won't be able to do that till I get a 2000p programable remote ignition module..
If only I new I could do this back in the day of "3 more HP" I might have hit my goal of 100/100.. Oh well, I'm way beyond that now because of the increase in cubic inches. Here's a look at the way the curve is now in the RED dots.. Each line on the pickup represents 2.5 degrees of timing which is the same as in the graph.. I might need to add a little more fuel but I want to put a few hundred more miles on the plugs to get a better reading.. Only 100 miles on these plugs.. Second pic shows timing on the strap and third pic show fuel burn..
I take it that you are still running those crappy D shaped chambers. Might want to bathtub them or find a better set..
I'm very happy with them.. 1.98" intake and 1.63" exhaust with a chamber size of 94.5 cc and a set of Axtell 30 degree pistons milled to 18.4 cc domes.. It all works very well together.. I'm pretty much done tearing down and redoing this motor, although I will have to tear it down eventually, I think the cases are leaking in the rear.. Will need to remove the primary to get a better look.. At that time I'll do the clutch.. It started slipping around 3800 rpm in 3rd@WOT.. I just want to get what ever power I can out of what i have..
The thing is being retired gives me a lot of time and when it's raining or the weather is shitty I get bored easily..
Last edited by 98hotrodfatboy; Mar 23, 2026 at 09:56 PM.
Agreed.. Similar to the necessity of dual plugged Shovels because of the piston...
I don’t know… while the dual plug looks good on paper it really didn’t improve performance for most streetable builds. Morons who just threw big dome pistons in shovel didn’t do great. Having a top heavy piston created it’s own issues and especially ware. For shovel and I gotta think evo too… the lowest dome possible to get the mechanical as close to 12:1 was the best street advice I could ever share. Adding the second plug was only needed when you had giant domes. And if you did it when you didn’t need it it lowered the mechanical compression.
In the context of shovel, I’m not qualified to speak about any other type of motor with this, I know everyone will say mathematically, my statement does not make sense. But the shovel hemi head for whatever reason, I always found responded better to stroke, then bore at the same cubic inch. For whatever reason the turbulence seemed greater with swept volume then with Bore. Heads that suck at flowing need all that angry turbulence in RPM to blow out and compensate for the poor head flow.
I’ve always been very very proud of being able to set up streetable shovels close to 12 to 1 and run on pump gas. And truthfully, most of these have been between 26 and 28° Full advance on anything from 93 to 103 in.ł. There’s no way I could do that with a dual plug set up. Believe me I tried over and over. To reach your compression goals you had to use a taller piston. if you had two spark plugs in there it lowered the compression, it never ran as efficient. The chamber was the key to raise mechanical. Lots of clay, dremmel and machining… tight tight tight chamber with low dome was key
flame propagation is a lot less of a concern these days with modern ignition systems and coils compared to the 50s - 70s.
You mentioned all the spark knock? Is there any chance that the cause is carbon buildup inside the chamber?
Last edited by Rains2much; Mar 24, 2026 at 09:04 AM.
I wasn't aware that was an option, I thought that chamber had to be opened up to accept the Pistons..
Well it definitely wouldn't work with the pistons you use but they do make tapered squish pistons.. Filling that area in has been done. The evo SE heads have squish both sides. Branch used to weld up the D shaped heads and kidney shape the chambers.. He used a flat squish but but they could be tapered. IIRC Axtel had pistons.
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New Ignition Curve...
